Electrophysiological studies with cats and monkeys and psychophysical studies with humans will be conducted to investigate the effects of adaptation on receptive field organization and the spatial and temporal response properties of the visual system. Recordings from single units of the cortex, LGN and retina will be made under computer control employing a variety of different targets, stationary, moving, and of varying spectral characters. Psychophysical studies will investigate simple orientation discrimination as influenced by adaptation --- retinal region stimulated and temporal distribution of the stimulus components. Monocular and haploscopic studies will be performed and depth discrimination process will also be considered.